This invention relates to stabilizers used in drilling with down hole percussors.
It is known to provide a stabilizer comprising a tubular mandrel for insertion in a drill string and a sleeve having radially extending wall engaging blades, the sleeve being releasably secured to the mandrel for easy replacement when worn. See for example U.S. Pat. No. 3,754,609 to Garrett and the references therein discussed.
It is known to provide positioning means around down hole motors of various types. See for example United States patent application Ser. No. 419,106 filed Nov. 26, 1973 by Kellner and the continuation thereof Ser. No. 505,450 filed Sept. 13, 1974 and the continuation-in-part thereof being filed approximately contemporaneously herewith and the prior art discussed therein, e.g. U.S. Pat. Nos. 3,561,549 to Garrison et al, 2,637,527 -- Andrews, Jr., and 3,399,738 to Haspert.